1. Field of the Invention
The present invention relates, generally, to a method and system for the secure use of a network service and, more particularly, to such a method and system using a blackboard on which all usable services are entered and, upon detection of a service which has not yet been entered on the blackboard, a check is made to determine whether use of this service is admissible and, if so, the service is entered under the blackboard.
2. Description of the Prior Art
The extension of networks is usually administered centrally today. If a new network element is added, it is necessary to ensure that it “gets on” with the network elements which are already available; that is, a syntactically and semantically correct interface to the network is stipulated and appropriate interface drivers, also called “stubs,” are used. Stipulating such interfaces is usually time consuming and very susceptible to errors, particularly between systems from different manufacturers, because, for example, it is then usually possible to network together only interface drivers which are based on the same interface version.
One concept for a more flexible extension of networks is “Plug & Play (PnP),” where each network element specifies its interface using a specific interface description language, and services of the network element are accessed using interface drivers which are produced using the interface specification. An example of one application of the PnP concept is in “ad-hoc networks,” in which network elements from different manufacturers respectively make their services available to those network elements which are currently integrated in the ad-hoc network; there being no prior stipulation as to which interface is possessed by the respective network elements. A brief description of this novel network type can be found in Claudia Piemont, “Geistreiche Verbindungen-Intelligente Geräte in dezentralen Netzen” [Smart connections-Intelligent devices in local area networks], c't, No 20, 1998. Products in the PnP field are currently being developed at Sun (Jini™), Hewlett Packard (JetSend), Lucent (Inferno) or Microsoft (uPnP=Universal Plug & Play1), for example.
The text below describes the Jini™ mechanisms from Sun by way of example. However, this constitutes no restriction for the inventive mechanisms, which can be used generally. The architecture and mechanisms of Jini™ are described in Sun Microsystems, “Jini™ Architectural Overview”, Technical White Papers2, January 1999. Ad-hoc networks, such as that of Jini™, are distinguished in that network elements, and hence also the services they provide, can be added to and removed from a network arbitrarily.
Services are understood as being an agency which can be used by a person, a program or another service. By way of example, they may be hardware, software, filters, a communication channel, memory space and much more. To deal with an overall object which is set, it may be necessary to use a large number of individual services. The services which are currently available and can thus be used in each case are registered on “blackboards,” sometimes, also called “lookup functions.”
The blackboards also control the addition and removal of services to and from the network at arbitrary times. Network elements are able to communicate, or “join” their existence and their services to a blackboard. A blackboard is also able to search for network elements providing services, also called “lookup” or “discovery.” For use of the services, a leasing mechanism is provided. In this context, a period for use is agreed between the agencies involved, after the expiration of which the resources of the used service are released again. The use of services, and hence the communication which is necessary in this regard, is effected using Java Remote Method Invocation (RMI™), for example, the structure of which is comparable with the tried and tested Remote Procedure Calls (RPC).
The Jini security architecture is designed such that each service has an owner and is equipped with access control; i.e., the service has the identity of its owner. This owner generally also defines the system's use rights, at least for those services which it makes available to the system. If a first service now uses a second service, this use takes place with the identity of the second service. Whether access is permitted depends on the access control of the first service. In this regard, cf. also Richard Sietmann, “Jini organisiert das Netz selbst” [Jini organizes the network itself], Funkschau, No 23, page 84, section “Sicherheit bei Jini” [Jini security], 1 st paragraph, 1998. This concept requires local administration of use rights. In addition, a service for which no access control is provided is available to all the network elements in an ad-hoc network.
The present invention is thus directed to improving the secure use of a network service.